Hey all,
I'm gonna go with 4:88s down the road for my current 33s, so I can make the jump to 35s in the future because 373s, nv3550 with 33s SUCKS. Don't let anyone fool you otherwise. I plan to go with revolution gears 4:88, and can someone tell me if I need the master overhaul kit with bearings and all that? Id like to have all the parts in hand and bring it to a shop to install. Also ive heard talk of "thick cut" gears or something like that, which is a set that doesnt need to be broken in? I have heard that they tend to be weaker, correct me if im wrong. If someone would also post links as to where to get them id appreciate it.
My strongest possible recommendation is for you NOT to buy any of the parts, gears, master install kit, etc. with the intention of providing the parts to a shop you'll be using to install them. Let the shop provide ALL (!) of the parts needed for the job, don't provide them ANYTHING other than your Jeep.
The reason is that if ANYTHING goes wrong during or after the gears are installed, the shop can and likely will point their fingers at and blame something about the parts you provided. If that happens you're in a world of hurt because even with the parts having their own warranties, then you are stuck in the middle of the parts dealers blaming the installation process and the installer blaming your parts. And it is rare for the parts to cause any problems, it's nearly always the installer's fault since the installation job is very exacting and if not done perfectly, the new gears will be toast in short order.
And even if you got the dealer you bought the gears/parts from to replace them under warranty, you'll still be faced with paying the additional labor to replace the gears since, again, the installer won't usually admit to having screwed up the installation.
If they provide ALL of the parts, their warranty will cover everything, parts and labor, no questions-asked.
Odds are good you can tell them you want Revolution Gear and they'll get them. If they can't because they're not a dealer for Revolution, let them install the gear brand they are comfortable with. 4.88 is a standard ratio and any mainstream brand like Genuine Gear, Yukon, etc. will be fine.
And to explain the thick-gear thing yet again.... it's a thicker version of the ring gear. That is so you won't need a different carrier designed for lower ratios like 4.88. The pinion gear on 4.88 gears is smaller in diameter so with a standard carrier, it won't position the ring gear close enough to the smaller diameter pinion gear so they fully mesh. A carrier meant for a lower ratio like 4.88 positions the ring gear closer to the pinion gear so they mesh properly.
But if you have a carrier meant for ratios like 3.07 or 3.73, as you do, your existing carrier won't position the ring gear close enough to the pinion gear so its teeth can mesh properly with the pinion gear. In that case you can install a 'thick' ring gear that positions its teeth further out so they are properly positioned to mesh with the pinion gear.
I am well aware of the slower crawling offroad, and that was originally leading me towards them, but my concern primarily was cruising on the freeway at 3k rpm. Does that do no harm to the engine? And can will 5:13 fit in my dana 30? Another reason I had wanted 4:88s was because I did not want to do an axle swap as I thought 4:88s were the lowest you can go in a dana 30
